This invention relates to inflations for teat cup assemblies of vacuum-operated milking machines and, more particularly, to such inflations including a milking tube section which is attached to a nipple on a milker claw.
Vacuum-operated milking machines typically include a milker claw having four ferrules or nipples. A teat cup assembly including a flexible (e.g., rubber) liner or inflation is attached to each milker claw nipple. During the milking operation, the teat cup assemblies are suspended from a cow's teats and milk flows through the inflation under the influence of a vacuum maintained in the claw. After a teat cup assembly is removed from a teat upon completion of milking, the inflation is suspended from the claw nipple in a manner to shut off communication between the claw and the atmosphere and thereby preserve the vacuum in the system.
When the claw is pulled away from a cow, either manually or automatically, the claw end portion of the inflation, can be bumped against surrounding equipment, objects, etc. and often strike the ground quite hard, particularly at dairies with automatic take-offs. Also, cows frequently step on inflations in the region of the claw nipples. This can result in the portion of the inflation beneath the claw nipple being damaged.
One approach for minimizing this problem is to provide the claw end portion of the inflation with an enlarged reinforcement section in the region near the outer end of the claw nipple. However, as the reinforcement section is thickened to improve its impact protection, the resulting stiffness reduces the vacuum shut-off capability and also makes it more difficult to connect the teat cup assembly to a teat. This stiffness also transmits a significant sideways force to the teat, which can cause undesired atmospheric air to be admitted and contribute to liner slippage.
Representative prior inflation constructions designed to facilitate vacuum shut-off and/or minimize inflation damage from bumping are disclosed in the following U.S. patents:
______________________________________ Patentee U.S. Pat. No. Issue Date ______________________________________ Green 2,099,884 November 23, 1937 Scott 2,341,953 February 15, 1944 Hein 2,694,379 November 16, 1954 Norton 3,611,993 October 12, 1971 Olander 4,196,696 April 8, 1980 Larson 4,324,201 April 13, 1982 ______________________________________
None of these patents discloses an inflation including a reinforcement section which is specifically designed to minimize damage from bumping or crushing from beneath the claw nipple and yet permit good vacuum shut-off and facilitate bending for connection to a teat without imparting excessive sideways forces on the teat.